This type of system or method is employed in a very wide diversity of applications for computer-aided creation of graphics and texts as well as in CAD applications.
This type of system or method is employed especially in automation technology for design, implementation or commissioning of plant and machinery. To keep the outlay for such engineering tasks as low as possible efforts are usually made to refer back to existing components and modules, from old projects for example, and to adapt these to the requirements of current projects.
If for example a number of chain conveyors are needed in a project and if a corresponding element already exists for describing a chain conveyor in information technology terms, one solution would be to transfer this element into the current project and adapt it to the project-specific demands.
For software implementation of a number of chain conveyors copies of the element are created. When the copies are created there is often the desire for changes made to the element to be effective for all chain conveyors contained in the project. The methods which exist for this type of retrospective modification of all copies are currently as follows:
In the type concept a user deliberately creates a re-usable information unit—the type. The user can form entities which refer to the type. Parameters can be defined for the type on the basis of which entity-specific modifications can be made. The entity points to the type and uses the structure and the behaviour of the type directly. This means that the basic behaviour of an entity can only be modified by modifying the associated type. The link between entity and type is strict, i.e. the entity is not capable of existence without the type.
With the template concept the user similarly creates a re-usable information unit—the template. Unlike the type concept however, in this case the user perceives an entity based on the template as a copy of the template and at the same time as a self-contained information element. Entity-specific changes can be made by the user by modifying the entity. The system detects whether modifications made are to be interpreted as setting of parameters for the entity or must lead to a removal from the original template.
By contrast with the type concept, modifications can be made in the template concept both to the template and also to the entities. The template behaves like an entity for the user. If the template is modified the change can be transferred automatically, or if required, manually by the user to all entities linked to the template, in which case the entity-specific modifications are not overwritten.
What both the type concept and also the template concept have in common is that users can form their own re-usable information unit and thus have the opportunity to modify entities and copies of entities by modifying the type or the template in the same way. The changes however only affect all copies of an entity if all copies and also the original entity are linked to the template or to the type.
For copying of basic elements—elements which are inherent in the system—no link is created in current systems between the original basic element and its copy. Basic element and copy behave as two independent entities.